If you look at that 5-round group you might think it was shot with a 6 PPC or maybe a 6mmBR. But no, this was done with heavy 180gr Berger Hybrid bullets and the .284 Shehane, an improved version of the .284 Winchester. In fact, this impressive sub-quarter MOA group was shot while fire-forming with a very well-worn barrel!
Here’s a 5-shot 0.191″ group at 100 yards with my .284 Shehane fireforming loads. This barrel has 2200 rounds through it. It had 2000 as a straight .284 Win and then I set it back to .284 Shehane to form brass with. This was the first five rounds through it after I cleaned it after the last match. [The load was] 180 Hybrids with 54.0 grains of H4831 SC.
Ya, I figured why not I had some old barrels laying around so I just chopped 2″ off the back and 1″ off the front and chambered it up as a Shehane. Had 1000 pieces to fireform and didn’t want to do all that on a brand new barrel.
My fireform loads are going 2765 FPS. I have a 29″ barrel also though since it’s a setback. Once you get it formed I would push it faster than that or I wouldn’t even bother with the Shehane. My old straight .284 load at 2890 fps had ES spread in single digits for 10 shots. I figured if I get it up to 2935-2950 fps that will be a point or two saved in a several day match.
Fellow .284 Shehane shooter Erik Cortina notes that the .284 Shehane has a velocity edge over the straight .284 Win because it holds more powder: “The Shehane has more capacity than the .284 Winchester. Ryan is using 54.0 grains simply as a fire-forming load. Typical load for a Shehane is around 57.0 grains of Hodgdon H4831 SC.” By blowing the sidewalls out 0.010″, the .284 Shehane picks up about 3.3 grains of extra case capacity. That enhancement makes a BIG difference. The extra boiler room is enough to drive the 180s at 2900-2950 fps with H4831sc, with long barrels.
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Ruprecht Nennstiel, a forensic ballistics expert from Wiesbaden, Germany, has authored a great resource about bullet behavior in flight. Nennstiel’s comprehensive article, How Do Bullets Fly, explains all the forces which affect bullet flight including gravity, wind, gyroscopic effects, aerodynamic drag, and lift. Nennstiel even explains the rather arcane Magnus Force and Coriolis Effect which come into play at long ranges. Nennstiel’s remarkable resource contains many useful illustrations plus new experimental observations of bullets fired from small arms, both at short and at long ranges.
Shadowgraph of .308 Winchester Bullet
A convenient index is provided so you can study each particular force in sequence. Writing with clear, precise prose, Nennstiel explains each key factor that affects external ballistics. For starters, we all know that bullets spin when launched from a rifled barrel. But Nennstiel explains in greater detail how this spinning creates gyroscopic stability:
“The overturning moment MW tends to rotate the bullet about an axis, which goes through the CG (center of gravity) and which is perpendicular to the plane of drag, the plane, formed by the velocity vector ‘v’ and the longitudinal axis of the bullet. In the absence of spin, the yaw angle ‘δ’ would grow and the bullet would tumble.
If the bullet has sufficient spin, saying if it rotates fast enough about its axis of form, the gyroscopic effect takes place: the bullet’s longitudinal axis moves into the direction of the overturning moment, perpendicular to the plane of drag. This axis shift however alters the plane of drag, which then rotates about the velocity vector. This movement is called precession or slow mode oscillation.”
Raise Your Ballistic IQ
Though comprehensible to the average reader with some grounding in basic physics, Nennstiel’s work is really the equivalent of a Ph.D thesis in external ballistics. You could easily spend hours reading (and re-reading) all the primary material as well as the detailed FAQ section. But we think it’s worth plowing into How Do Bullets Fly from start to finish. We suggest you bookmark the page for future reference. You can also download the complete article for future reference and offline reading.
Sierra Bullets recently profiled Mike Walker, Remington engineer and first president of the National Benchrest Shooters Association (NBRSA). In the vintage photo above, Mike is shown with his Remington-actioned benchrest rifle at the 1994 Super Shoot. Mike had reason to smile — at that 1994 event, Walker set a 100-yard small group record with a phenomenal .046″ five-shot group. Mike was truly one of the “founding fathers” of modern benchrest shooting. As Sierra notes: “The field of rifle accuracy and the sport of benchrest shooting would be very different today, were it not for this man.”
Along with Remington Engineer Jim Stekl, Mike Walker helped develop a wildcat that became the 6mmBR cartridge. The original 6mm Benchrest Remington wildcat was a necked-down .308 x 1.5″ Barnes cartridge. That Barnes cartridge was derived from the .308 Winchester case, as shortened to 1.5 inches. The parent .308 Win case has a large primer pocket (though Remington did make a special run of small primer pocket .308 brass). Remington later made factory small primer pocket 6mm BR Rem brass. Compared to the original 6mm BR Remington case, the modern 6mmBR Norma cartridge has very slightly different dimensions, with a small primer pocket and a small 1.5mm (0.059″) flash-hole.
In the not-too-distant future, U.S. military snipers may be able to steer bullets right to the target, thanks to DARPA, the Defense Advance Research Projects Agency. Believe it or not, DARPA has developed a guided .50-caliber projectile fired from a conventional rifle action. DARPA’s Extreme Accuracy Tasked Ordnance (EXACTO) system combines a maneuverable bullet and a real-time guidance system to track and steer the projectile to the target. Inside EXACTO bullets are optical guidance systems, aero-actuation controls, and multiple sensors. The top-secret technology permits the trajectory of the bullet to be altered in flight, allowing the bullet to move left or right, or even fly in an arc around an obstacle.
Following Sierra’s introduction of Tipped MatchKing (TMK) bullets, Bryan Litz of Applied Ballistics LLC has received many requests to determine the Ballistic Coefficient (BC) of these bullets through testing. Below are Litz’s findings for four out of the six bullets he has able to acquire and test so far.
As you can see from the above table, when Sierra’s G1 BC is averaged for all speed ranges (which is representative of long range shooting) the results closely match the Applied Ballistics’ measurements of the same bullets, averaged from 3000 to 1500 FPS. The G7 BC doesn’t suffer nearly the velocity sensitivity as G1 and should be used for modern long range bullets when possible. Bryan tells us: “When I get the .22 caliber 77gr, and the .308 caliber 168gr tested, I’ll update the table.”
How do these Tipped MatchKings compare to standard MatchKings? According to Bryan’s measurements, here are some comparisons:
The 69gr TMK BC is +8% compared to the 69gr SMK
The 125gr TMK BC is -5% compared to the 125gr SMK (Litz believes this SMK was ‘pointed’)
The 155gr TMK BC is identical to that of the 155gr SMK (#2156, which is also pointed)
The 175gr TMK BC is +10% compared to the 175gr SMK
Bryan provided this additional advice for users of Ballistics programs: “Sierra’s stated BCs are measured by live fire, and are typically pretty accurate if the velocity bands are properly observed (7mm being the exception). A common error is to look at the BC that Sierra gives for your MV and just use that. Doing so overestimates the performance of the bullets over long range, and will cause you to hit low compared to your trajectory predictions.”
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OK, guys, it’s time to practice your downloading skills. Here’s a very handy cartridge information sheet you will definitely want to save for future reference. Shown below is Page One of the Primer Size and Bullet Diameter Chart created by Graf & Sons. This chart shows the bullet diameter and primer size for more than 320 popular cartridges*. The full three-page chart is available in PDF format for easy printing.
NOTE: If you have the PDF reader installed in your browser, the Graf’s Chart may open in a new tab when you click on the image above. To save the three-page PDF file to your computer or device, click the Floppy Disc icon that appears in the lower right (after the PDF file opens). Here is the direct link:http://www.grafs.com/uploads/technical-resource-pdf-file/12.pdf.
Note: There are a few mistakes. If you are making 22 BR from Lapua brass, you’ll want a small rifle primer. Likewise with 25-20 WCF, you want a small primer.
Resource Tip from EdLongrange. We welcome reader submissions.
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What cartridge would your chose to hit targets at long range … extremely long range, as in 2500 yards? Well, for ace competitive shooter Darrell Buell, the answer is the .338 Allen Magnum, a .408 Cheytac necked down to .338. This “super-sized” cartridge flings .338-caliber, 300-grain Berger Hybrid bullets at 3450 fps. That delivers some impressive ballistics at ultra-long range. Darrell got to “test-drive” a .338 Allen Magnum rifle at 2500 yards (1.42 miles) while teaching a Long-Range Seminar at the Legion Operator Training Group (OTG) Facility in Blakely, Georgia.* The rifle belonged to Christopher Sykes.
Shown below is the 338 Allen Magnum (AM) next to a .308 Winchester round loaded to an extremely long OAL. The .338 Allen Magnum is a wildcat based off the .408 Cheytac (Cheyenne Tactical) parent case. The cartridge’s inventor, Kirby Allen, states: “The .338 Allen Magnum, when loaded with a 300gr SMK, offers a legit 500 to 600 FPS velocity advantage over the 338 Lapua Magnum”.
Darrell says: “Yeah, it’s a beast [but] with that brake, it kicks less than my .308 competition rifle. It’s got more energy at 2500 yards than a .45 ACP has at the muzzle. The .338 Allen cartridges are standing next to the SEB Joy-pod, along with a standard .338 Lapua Magnum cartridge. With the excellent muzzle brake on the .338 Allen, I could spot my own hits with just the slightest twitch of the joystick. The rifle was not particularly heavy, consequently the pod would hold the crosshairs where you left them without a hand on the joystick.”
When you look at a loading manual with load data, you will usually see pressure ratings for stated load. Sometimes these are listed in PSI numbers, which most people correctly understand to be Pounds per Square Inch of pressure. However, powder-makers also commonly list pressure in CUP numbers. CUP stands for Copper Unit of Pressure. You may be asking — “What exactly is a CUP, and what is the origin of that unit of measurement?” You may also be wondering — “What’s the difference between CUP pressures and PSI pressures?” On Hodgdon’s Facebook Page, you’ll find answers to these questions.
Q: What is CUP?
A: Copper Unit of Pressure (CUP) is a measurement used in the ammunition industry to determine the chamber pressure created by a cartridge load. Originally, a precisely formed copper slug was placed in a fixture over the chamber. When the cartridge was fired, the amount of crushing measured on the slug allowed engineers to determine the pressure.
These days, modern electronic transducers provide faster, more accurate measurements of chamber pressures in pounds per square inch (PSI). CUP and PSI are measured to different scales and are NOT interchangeable.
Hodgdon Reloading Data Center Sample
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Are you bored with your “whimpy” .50 BMG? Looking for something with a little more punch? Well J.D. Jones and his team at SSK Iindustries have created a truly big boomer — the .950 JDJ. As its name implies, rifles chambered for the cartridge have a bore diameter of 0.950″ (24.13 mm). This would normally make such rifles “destructive devices” under the 1934 National Firearms Act (NFA). However, SSK obtained a “Sporting Use” exemption allowing the rifles to be sold without special restrictions as destructive devices. CLICK HERE to watch .950 JDJ being fired.
.950 JDJ Specifications
Rifle Cost: $8000.00
Ammunition Cost: $40.00 per round
Projectile Weight: 3,600 grains (more than half a pound)
Rifle Weight: Between 80 and 120 pounds
Muzzle Energy: 38,685 ft/lbs (52,450 Joules)
Momentum: 154.1 Newton-seconds
As crafted by SSK Industries, .950 JDJ rifles use McMillan stocks and very large-diameter Krieger barrels fitted with a massive 18.2-lb muzzle brakes. The ammo produced by SSK features solid 3,600 grain bullets and CNC-machined cartridge brass. It is also possible (through a lot of work), to use a 20mm cannon casing shortened and necked-down.The primer pocket is swaged out to accept a .50 cal machine gun primer. That 3,600 grain bullet is just massive — it weighs more than half a pound. The cartridge propels its 3,600 grain bullet at approximately 2,200 fps. This yields a muzzle energy of 38,685 ft-lbs and a momentum of 154.1 Newton-seconds. The energy on target (knock-down power) is comparable to WWI-era tank rounds.
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Here’s a great video from German ammo-maker GECO (part of the Swiss RUAG group of companies). Employing advanced 3D rendering and computer graphics, this animation unveils the inside of a pistol cartridge, showing jacket, lead core, case, powder and primer. Next the video shows an X-ray view of ammo being loaded in a handgun, feeding from a magazine.
Then it really gets interesting. At 1:32 – 1:50 you’ll see the firing pin strike the primer cup, the primer’s hot jet streaming through the flash-hole, and the powder igniting. Finally you can see the bullet as it moves down the barrel and spins its way to a target. This is a very nicely-produced video. If you’ve ever wondered what happens inside a cartridge when you pull the trigger, this video shows all. They say “a picture’s worth a thousand words”… well a 3D video is even better.
For Best Viewing, Click Gear Symbol and Select HD Playback Mode
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Shoot 101 Quiz
Vista Outdoors (formerly ATK Sporting Group) has launched a new multi-platform media campaign called Shoot 101. Combining print, web, and television, Shoot 101 provides “how to” information about shooting, optics, and outdoor gear.
On the Shoot 101 website, you’ll find a Ballistics Quiz. The questions are pretty basic, but it’s still fun to see if you get all the answers correct.
You don’t need a lot of technical knowledge. Roughly a third of the questions are about projectile types and bullet construction. Note, for some reason the layout doesn’t show all the possible answers at first. So, for each question, be sure to scroll down using the blue scroll bar on the right.
By Dennis Santiago
Competition teaches you things. Compared to loading for benchrest bolt guns, producing ultra-reliable and accurate ammo for tight-chambered, semi-auto .308 target rifles requires a different approach to case prep. Smoothness of operation is much more important in a field course gun. Reliability trumps everything (even case life) for these types of guns.
In the photo below, there’s a Redding small base body die for bumping the shoulder and making sure the case body is at SAAMI minimum. This body die is not just nice to have. It is vital. There are also a full-length sizing die and a Lee Collet neck-sizer in that turret holder. One or the other gets used after the body size die depending on what rifle the ammo will be used in. The semi-auto rounds always go through the full-length sizing die. After that comes trimming and finally cleaning — then loading can begin. The cases are trimmed using a Gracey trimmer so everything’s the same each and every time. I use an RCBS Competition Seater Die to seat the bullets. One nice feature of this RCBS die is the open side slot that allows you to place bullets easily.
It’s a long path methodology but uniformity is accuracy. More important for safety, controlling “stack-up” errors in the system solution is how one achieves reliability. The chamber-hugging philosophies of benchrest bolt guns do not apply well to AR-10s. Like most things, the right answer is context-dependent. Success is about accepting and adapting.
Dennis Talks About Using a Semi-Auto in Tactical Competitions
I have succumbed to the Dark Side — deciding to put an AR-10 together. For tactical competitions you want a bolt gun most of the time but there are times the course of fire favors the use of a semi-auto. I was using an M1A that gives me 0.75 MOA performance but I heard people were getting almost bolt-gun-level, half-MOA accuracy out of their AR-10s — so I wanted to see if that was really achievable. A quarter-MOA difference in accuracy potential may seem tiny in practical terms but it will make a difference in competition. In a match, the difference between 3/4-MOA and 1/2-MOA can alter your hit probability on a small target by 20-30%.
The AR platform also lets you tinker with triggers, stock ergonomics and muzzle brakes that help in managing the dynamics of a long distance shot better. Well I found out you can get the incremental accuracy but there’s more work to do to get the same reliability. Being a curious sort, it’s worth it to me to explore it. It’s a far cry from as-issued M-1 shooting with whatever HXP is handy. This is definitely swimming in the deep end of the pool.
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It’s not easy to place a first shot on target at 1500 yards. You must measure the wind speed with precision, know your exact muzzle velocity, and have a sophisticated ballistics solver. In this short video from Ryansrangereport.com, the shooter manages a first-round hit on a steel silhouette at 1500 yards. He used a Kestrel 4500 NV Weather Meter with Applied Ballistics software to figure out the trajectory for his 6.5 Creemoor rounds.
The Kestrel recorded a wind velocity, and the internal software calculated a solution of 17 Mils elevation (that’s 928 inches of drop) with 2.5 Mils windage. “Bang” — the shooter sends it, and 2.6 seconds later “Clang” he had a hit (flight time was 2.6 seconds). Bryan Litz observes: “This is the science of accuracy (in the form of an Applied Ballistics Kestrel) being put to good use at 1500 yards”.
Later in the video (1:05-1:15) the shooter places three rounds on steel at 1000 yards in just 10 seconds. The three shots all fall within 10″ or so — pretty impressive for rapid fire. The shooter reports: “[In my 6.5 Creedmoor] I’m using a 136gr Lapua Scenar L. This bullet has impressed me. It screams out of my barrel at 2940 fps and holds on all the way out to 1,500 yards.”
The rifle was built by Aaron Roberts of Roberts Precision Rifles (RPRifles.com). Chambered for the 6.5 Creedmoor, it features a Leupold Mark VI 3-18x44mm scope.
The 14th Edition of Cartridges of the World is a handy reference that contains illustrations and basic load data for over 1500 cartridges. If you load for a wide variety of cartridges, or are a cartridge collector, this book is a “must-have” resource. The latest edition (released in December 2014) includes 50 new cartridges. This important reference guide can be ordered through Amazon.com for $28.42 (or just $20.99 for a Kindle eBook version).
Cartridges of the World, the most widely-read cartridge reference book, has been totally updated, with a newly expanded, full-color 64-page color section featuring essays from some of today’s most prominent gun writers. The 14th Edition of Cartridges of the World (ISBN: 9781440242656) includes updated cartridge specs, plus essays by leading writers on the topics of SAAMI guidelines, wildcatting, and new cartridge design trends. Cartridges of the World is the most authoritative cartridge reference guide in print.
Cartridges of the World by author Frank C. Barnes was first published in 1965. The 14th Edition is edited by W. Todd Woodard, Editor of Gun Tests magazine and author of several firearms reference books. Frank Barnes (1918-1992) began collecting information on handgun cartridges at the early age of 12, thanks to his father, a police officer. Frank Barnes was an innovative cartridge designer, who invented the original 308 x 1.5″ Barnes, predecessor of the 30BR case.
Before Frank began a law enforcement career, he was a college professor. Frank was also a pilot, and a race-car driver. Learn more about Cartridges of the World (14th Ed.) at www.gundigest.com.
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The Lone Ranger used silver bullets… now you can too. Well, they’re not really silver, but they look like silver and they are lead-free. Norma’s new ECOSTRIKE™ bullet features a copper core with a proprietary silver-color plating to reduce fouling. Why is Norma offering a lead-free bullet? Well, in some locations, such as California, the use of traditional, lead-core bullets has been highly restricted. The Ecostrike give hunters the opportunity to shot hard-hitting, deep-penetrating projectiles, even where lead-cored bullets are banned. Norma explains: “The Ecostrike is designed to give… penetration deep enough to reach the vital organs even on large animals. The controlled expansion and a very high retained weight guarantee a consistent behavior and deep penetration.”
Being totally lead-free, Ecostrike bullets are California-compliant, and they can be used in other regions where lead ammo is restricted. Currently, Norma plans to offer Ecostrike bullets in four popular calibers: 7mm (.284), .308 (7.62 mm), 8mm, and 9.3 mm. Spanning the range from 7mm up to 9.3 mm, Ecostrike bullets will be available for the most popular big game cartridge types. Norma also plans to produce loaded ammunition featuring the new Ecostrike bullet.
“Silver Bullet” Bullion cartridges are produced by the NW Territorial Mint. The Norma Ecostrike bullets contain no silver, just copper and a proprietary plating. But they do look like silver bullets.
Product tip from EdLongrange. We welcome reader submissions.
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In January, during SHOT Show, Bullets.com President Shiraz Balolia inked a contract with Norma to produce ultra-high-quality .284 Winchester and 6mm Dasher brass. This was great news for competitive shooters. The .284 Win is the caliber to beat in F-0pen competition and the 6mm Dasher holds most of the records in the 600-yard benchrest game.
We’ve just learned that the new Norma .284 Win brass is in production and should be available in five to six weeks. Shiraz tells us: “Production is in full swing in Sweden and the picture below shows the very first .284 Win case that came off the line. They [.284 Win cases] are in testing and we expect to have them here in USA by the end of April.”
Bullets.com should start taking pre-orders in the near future. Shiraz explained: “As far as pre-orders for the Norma .284 Win brass go, we are waiting for final pricing. When we have that, we will make the .284 Win brass active on our Bullets.com website and will take orders. Those orders will be shipped in the order they were received.”
NOTE: This is just a QuickDESIGN drawing, NOT the Norma brass blueprint. Dimensions may vary slightly, so do not use this to spec reamers or other tools. Wait until you can measure the actual brass.
What about 6mm Dasher Brass from Norma?
Dasher fans will have to wait a little longer. Shiraz Balolia says: “It may be months for the Dasher brass. We will keep on them, but if I were to guess, it will be late summer 2015″.
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Add the Washington Post to the growing list of sources that credit President Obama with being the best salesman for firearms and ammunition that the country has seen since Samuel Colt. Using a simple linear trend analysis based on NSSF-supplied data, Washington Post writer Philip Bump calculated that the U.S. firearms industry has enjoyed a $9 to $10 billion increase in sales of guns and ammo during President Obama’s terms in office. CLICK HERE for full story in Washington Post.
Take a look at this chart — it shows a huge increase in sales of long guns, handguns, and ammunition during the Obama presidency. (NOTE: There is a decline at the extreme right of the chart because 2014 data only goes through the third quarter of the year.) You can seen why there have been shortages of ammunition. Look at the huge spike in ammo sales (orange zone) over the past six years. This may explain why some retailers ironically refer to the nation’s top elected official as “President ObAMMO”.
By comparing past industry sales numbers with figures for the past six years, the Washington Post calculates that the firearms industry has enjoyed a remarkable period of growth: “If you calculate out the difference between what might have been expected and what was, it’s about a $10 billion increase [in sales]”. We’ve seen evidence that things are cooling off, but according to the Washington Post: “The $9 to $10 billion in increase under Obama will keep growing, through the end of 2016. At which point gun manufacturers will probably be sad to see Obama go — even if gun buyers are not.”
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You’ve probably heard the term “Terminal Ballistics”. But do you really know what this refers to? Fundamentally, “Terminal Ballistics” describes the behavior of a projectile as it strikes, enters, and penetrates a target. Terminal Ballistics, then, can be said to describe projectile behavior in a target including the transfer of kinetic energy. Contrast this with “External Ballistics” which, generally speaking, describes and predicts how projectiles travel in flight. One way to look at this is that External Ballistics covers bullet behavior before impact, while terminal ballistics covers bullet behavior after impact.
The study of Terminal Ballistics is important for hunters, because it can predict how pellets, bullets, and slugs can perform on game. This NRA Firearm Science video illustrates Terminal Ballistics basics, defining key terms such as Impact Crater, Temporary Cavity, and Primary Cavity.
External Ballistics, also called “exterior ballistics”, is the part of ballistics that deals with the behavior of a non-powered projectile in flight.
Terminal Ballistics, a sub-field of ballistics, is the study of the behavior and effects of a projectile when it hits its target.
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